This invention relates to the arrangement and the construction of drums which can perform both inside and outside three folding operations and are applied to folding machines.
FIG. 7 shows a conventional folding machine for both inside and outside three folding operations.
The folding machine of this type has a cutter drum 1, a first folding drum 2, a first holding drum 3, a second folding drum 4, and a second holding drum 5. Each of these drums 1, 2, 3, 4 and 5 has a saw blade 1a (a member composing a drum is indicated by attaching a, b, c, and so on to the drum number); saw blade receivers 2a, needles 2b, and folding blades 2c; first holding means 3a and second holding means 3b which are interchangeable with each other or folding blades 3c; a pawl 4a and a folding blade 4c; and pawls 5a and holding means 5b, respectively.
When an inside three folding operation is performed by using this folding machine, a web A is drawn into the machine through first-stage nipping rollers 10 and second-stage nipping rollers 11 as shown in FIG. 8a to FIG. 8f. The web A drawn into the machine is caught by the sticking of needle 2b, and at the same time the leading edge of web A is cut by the saw blade 1a on the cutter drum 1 and the saw blade receiver 2a on the first folding drum 2 (refer to FIG. 8(a)). Next, the web A moves around the first folding drum 2 by being hooked by the needle 2b, and then is cut into a predetermined length by the saw blade 1a which has revolved one turn (refer to FIG. 8(b)). After that, a first fold is made on the web A at the position one-third length distant from the needle-side edge (hereinafter called needle-side 1/3 position) with the folding blade 2c on the first folding drum and the first holding means 3a on the first holding drum 3 (refer to FIG. 8(c)). Then, the web A is held by the pawl 4a on the second folding drum 4, and a second fold is made at the position one-third length distant from the first fold position (needle-side 2/3 position) with the folding blade 4c on the second folding drum 4 and the second holding means 3b on the first holding drum 3 (refer to FIGS. 8(d) and 8e)). The above-described operation completes inside three fold of web A as shown in FIG. 8(f).
This three-folded web, as shown in FIG. 7, being held by the pawl 5a on the second holding drum 5 in place of the holding means 3b on the first holding drum 3, is carried out of the machine through a carrying belt 6, an impeller 8, and a paper discharge conveyor 9. Alternatively, it is carried out of the machine through a carrying belt 6, a chopper 7, an impeller (not shown), and a paper discharge conveyor 9.
When an outside three folding operation is performed by using this folding machine, a web A is cut into a predetermined length in the same way as described above as shown in FIG. 9a to FIG. 9f. Then, a first fold is made at the needle-side 1/3 position with the folding blade 2c on the first folding drum 2 and the first holding means 3a on the first holding drum 3 (refer to FIGS. 9(a) through 9(c)). After that, the second fold is made in the direction reverse to the direction of the inside three folding operation with the second folding blade 3c which replaces the second holding means 3b on the first holding drum 3 and the holding means 5b on the second holding drum 5 (refer to FIGS. 9(d) and 9(e)). This operation completes outside three folding as shown in FIG. 9(f); the three-folded web is carried out of the machine.
The changeover from inside three folding to outside three folding is performed as follows: First, a clutch (not shown) is released, which is installed on the shaft of the second folding drum 4 driven by the first holding drum 3. Then, while the second folding drum 4 is fixed, the second holding means 3b (or the second folding blade 3c) on the first holding drum 3 is replaced with the second folding blade 3c (or the second holding means 3b), and the position of the first holding means 3a on the first holding drum 3 where the web leaves the drum is changed. In addition, the timing is changed on the chopper 7, the impeller 8, or the impeller not shown (for chopper folding) following the carrying belt 6. The changeover from outside three folding to inside three folding is performed in the way reverse to the way described above.
The above-described conventional method has the following problems:
(1) When the changeover from inside three folding to outside three folding or in reverse is performed, the second holding means 3b or the second folding blade 3c must be removed from the first holding drum 3, and replaced with the second folding blade 3c or the second holding means 3b. This replacing operation is complicated and time-consuming. In replacing, the position of the first holding means 3a on the first holding drum 3 where the web leaves the drum must be changed because some difference in position between the second holding means 3b and the second folding blade 3c arises. In order to adjust this position, a cam must be moved. The cam must be adjusted finely; if this fine adjustment is not made accurately, the accuracy of folding may decrease. PA0 (2) The second holding drum 5 is installed for an outside three folding operation. Therefore, an inside three folded web is discharged onto the carrying belt 6 from the drum 5 after it is received by the pawl 5a on second holding drum 5. This may cause easy shift in the position of the web, decreasing the accuracy of chopper folding and the accuracy of carrying to the impeller. As a result, some problems may arise with the postprocessing equipment. PA0 (3) When an inside three folding operation is performed, the needle hole comes inside. When cutting of the needle hole portion is needed as with catalogs, cutting is made to remove the needle hole portion. This requires cutting of the remaining two pieces of paper overlapping with the needle hole portion, excessive paper being consumed (loss of paper). PA0 (1) Both inside and outside three folding operations are performed by using two pairs of folding blades and holding means. PA0 (2) In both inside and outside three folding operations, folding is performed so that the needle hole comes outside. PA0 (1) A web A is cut into a predetermined length with the saw blade 1a on the cutter drum 1 and held by the needle 2b on the folding drum. On the web A, a first fold is made with the folding blade, 2c on the folding drum 2 and the holding means 21a on the first holding drum 21, and then a second fold is made with the folding blade 21c on the first holding drum 21 and the holding means 22a on the second holding drum 22. Thus, both inside and outside three folding operations are performed with the needle hole being outside. PA0 (2) The raising means for preventing interference raises the web A which is being three-folded, so that the leading edge of web B which follows the web A and the tip of needle 2b which holds the leading edge of web B do not come into contact with (not interfere with) the web A which is being three-folded. This provides satisfactory folds without edge folding or paper tearing of the web which is being folded. PA0 (1) Because the inside and outside three folding operations are performed by using two pairs of folding blade and holding means, the number of drums can be decreased as compared with the conventional folding machine for both inside and outside folding operations, resulting in a simplified construction of machine. In addition, because the number of operations to change holding is decreased, the shift of web is minimized, resulting in the increase in chopper folding accuracy and the carrying accuracy. PA0 (2) The changeover from inside three folding to outside three folding or in reverse is performed merely by moving the needle and saw blade receiver and saw blade which have no direct effects on the folding accuracy; there is no need for replacing the holding means and folding blade which have effects on the folding accuracy as with the conventional folding machine. Therefore, the cam for adjusting the folding timing of these members requires no frequent adjustment, good folding accuracy being maintained. PA0 (3) By using the raising means for preventing interference, the leading edge of the web following the web which is being folded does not interfere with the latter web. This eliminates the problems of edge folding and paper tearing. PA0 (4) The needle hole comes outside for both inside and outside three folding operations, so that only a sheet of the outside folded portion with needle hole is cut for the folds on which the needle hole portion must be cut in inside three folding operation, such as catalogs, resulting in the saving of paper (decrease in paper loss).
In addition, a clutch must be installed to disengage the driving of the second folding drum 4 from the first holding drum 3.
Further, the timing of components following the carrying belt must be changed in accordance with the adjustment of cam.